1. Field of the Invention
The present invention relates generally to an assembly for connecting a sling, cable, or other lifting device to a load to be lifted. More particularly, the present invention relates to a shackle apparatus that is permanently attached to a set of slings, lifting cables or the like. More particularly still, the present invention relates to a captivated shackle apparatus that must also be discarded when attached slings or lifting cables are discarded.
2. Brief Description of the Prior Art
Numerous devices have been devised for the purpose of lifting baskets, skids and/or similar equipment, especially in connection with the transportation of said baskets, skids and/or equipment from one location (such as, for example, the deck of a boat) to another location (such as, for example, an offshore platform) using a crane, hoist or other lifting means. In the course of such lifting operations, consideration must be given to maintaining control of a load during the lifting process. Consideration must also be given to other factors, such as ease in making connections and disconnections to such load, as well as the protection or preservation of the load being transported. Perhaps more significantly, consideration must also be given to minimizing possible failure locations on the item(s) being lifted, as well as the related lift equipment, in order to prevent damage to property or personnel.
During lifting operations, large or heavy loads are typically lifted using a set of slings connected to the line of a crane, or hoist or other lifting apparatus. Although it is often possible to connect a crane or hoist line directly to a load to be lifted using shackles or the like, slings generally provide an intermediate means to quickly and efficiently connect a lifting device to a load. Further, because many slings utilize two or more separate lines connected to a central link or loop, slings are generally preferred because they allow for more even weight distribution during the lifting process.
The use of slings to lift and/or transport equipment, cargo or other loads is very common in offshore or marine operations, as well as numerous other applications, such as the loading and unloading of ships and other vessels. It should be noted that the offshore oil and gas industry, although representative of the issues faced in the lifting and transportation of heavy loads, is but one application involving such issues.
The use of lifting slings or cables as an intermediary link for connecting a load to a lifting device (such as a crane hook or the like) is well known. In conventional lifting applications, a lifting sling normally has a plurality of cable legs of substantially equal length, which are joined together at their upper ends and are coupled to a common, master connection assembly. In most instances, said master connection assembly is a loop dimensioned so that it can easily connect to a crane hook. Each cable leg of the sling is normally fitted with a looped terminal end which is formed using a mechanical joint or crimped band.
In many instances, shackles or other means can be used to connect the individual lines of a set of slings to pad-eyes of a load to be lifted. Specifically, a shackle or clevis is commonly used to connect each looped end of a sling or lifting cable to a load to be lifted. In conventional lifting applications utilizing existing shackle assemblies, a substantially U-shaped shackle having a mouth or opening is passed through the loop or eye of a sling or lifting cable. Thereafter, a bolt is threaded through aligned bores in said shackle and an opening in a lift lug or pad eye of a load to be lifted. In this manner, the shackle provides a quick and efficient means for affixing a sling, cable, or other lifting device to a load to be lifted.
Safety regulations and customary safety procedures often dictate that lifting slings or cables be discarded after a predetermined threshold is met, such as a certain period of time or number of lifts. Despite such safety regulations and/or procedures, it has been observed that shackles are often removed from such lifting slings or cables prior to discarding of the slings or cables. The removal of shackles from such slings and re-use of such shackles on other slings or lifting cables defeats the purpose of the aforementioned safety practices. As such, it would be beneficial to provide a captivated shackle apparatus permanently attached to a set of lifting slings or cables that must be discarded along with such attached slings or lifting cables in order to ensure that such shackles are not re-installed or re-used on other slings or lifting cables.